The subject matter disclosed herein relates to strain sensors and, more specifically, to methods and devices for determining strain on turbine components for high temperature applications.
In gas turbine engines, such as aircraft engines for example, air is drawn into the front of the engine, compressed by a shaft-mounted rotary-type compressor, and mixed with fuel. The mixture is burned, and the hot exhaust gases are passed through a turbine mounted on a shaft. The flow of gas turns the turbine, which turns the shaft and drives the compressor and fan. The hot exhaust gases flow from the back of the engine, driving it and the aircraft forward.
During operation of gas turbine engines, the temperatures of combustion gases may exceed 3,000° F., considerably higher than the melting temperatures of the metal parts of the engine which are in contact with these gases. Operation of these engines at gas temperatures that are above the metal part melting temperatures may depend in part one or more protective coatings and/or on supplying a cooling air to the outer surfaces of the metal parts through various methods. The metal parts of these engines that are particularly subject to high temperatures, and thus require particular attention with respect to cooling, are the metal parts forming combustors and parts located aft of the combustor.
Moreover, the turbine components may experience stress and/or strain from various forces over its operational lifecycle. While various tools may be utilized to measure imparted stress and strain in relatively standard environments, the turbine components in turbine engines may experience hotter and/or more corrosive working conditions that may be unsuitable for such measurement tools. Moreover, any potential strain may vary from location to location. Therefore, merely measuring a change of distance between only two points may provide limited data on any actual strain locations within that region.
Accordingly, alternative methods and devices for determining strain on turbine components for high temperature applications would be welcome in the art.